// We can add style names to widgets
sendButton.addStyleName("sendButton");

// Add the nameField and sendButton to the RootPanel
// Use RootPanel.get() to get the entire body element
RootPanel.get("nameFieldContainer").add(nameField);
RootPanel.get("sendButtonContainer").add(sendButton);
RootPanel.get("errorLabelContainer").add(errorLabel);

// Focus the cursor on the name field when the app loads
nameField.setText("06");
nameField.setFocus(true);